Is the Cullinan Diamond a royal gift or a gem acquired through questionable means?

In 1905, the Premier Mine near Pretoria, South Africa, had been operational for only two years but was already one of the world’s leading diamond mines. One day, the mine's superintendent was conducting a standard inspection 18 feet below ground when a flash of light from a rock caught his eye. He extracted a large chunk, assuming it to be a worthless piece of rock crystal.

At first, he believed a rock of that size — more than a pound and roughly the shape of a human heart — could never be a diamond. He was mistaken. It was the Cullinan diamond.

The Great Star of Africa: The Cullinan Diamond

Named after Thomas Cullinan, the owner of the Premier Mine, the Cullinan diamond is still regarded as the largest gem-quality diamond ever discovered. In its rough form, it weighed 3,106 carats and measured approximately 4 inches by 2.5 inches by 2.3 inches (10.1 by 6.35 by 5.9 cm). To put it into perspective, the famous blue Hope Diamond weighs just over 45 carats.

In 1907, the massive rough stone was presented to King Edward VII as a gift. It was then divided into nine diamonds, labeled Cullinan I to Cullinan IX, ranked from largest to smallest.

The Cullinan I, famously known as the 'Great Star of Africa,' is the largest colorless cut diamond in existence. Weighing over 530 carats, it is set in the Sovereign's Scepter, a vital part of the British royal family's priceless crown jewels. The Cullinan II, which weighs a solid 105.6 carats, is the second-largest cut diamond and serves as the dazzling centerpiece of the Imperial State Crown.

The Cullinan diamonds are not only among the largest cut diamonds globally but also some of the most stunning, showcasing all the prized qualities of gem diamonds. According to Evan Smith, a senior research scientist at the Gemological Institute of America (GIA), the organization that assesses diamonds based on the 'four Cs'—cut, clarity, color, and carat weight.

"The Cullinan diamonds are the epitome of perfect color, size, and clarity," says Smith. "They represent the ultimate in diamond excellence — diamonds that are fully colorless and nearly flawless inside."

The Queen, Colonialism, and the Cullinan Diamond

When Queen Elizabeth II passed in 2022, Cullinans I and II were prominently showcased. Alongside the crown and scepter, a third item, the Sovereign's Orb, was placed on the Queen’s casket as part of the funeral procession, which was broadcast globally.

While world leaders celebrated Queen Elizabeth's dignity, strength, and grace during her unprecedented 71-year reign, some critics highlighted that she never made a formal apology for Britain’s colonial past, which included rule over South Africa from 1795 to 1961. The Cullinan diamond’s discovery and subsequent sale are deeply tied to this colonial legacy.

The Premier Mine, where the Cullinan diamond was unearthed, was situated in the area once known as the Transvaal. In the early 1800s, Dutch settlers, known as Boers, fled the British-controlled Cape Colony and made their way to South Africa’s arid interior near present-day Pretoria, where they defeated local tribes and established the Transvaal Republic.

The Rocks That Built South Africa

In 1867, a young boy of 15 named Erasmus Jacobs, the son of a humble Boer farmer, stumbled upon a gleaming rock on his barren land. After being persuaded by neighbors, he sent the stone to British authorities in the Cape Colony, where tests revealed that it was a 21.25-carat diamond later named the Eureka Diamond.

"This diamond," wrote the British Colonial Secretary of the time, "is the stone upon which the future prosperity of South Africa will be built."

The discovery of diamonds in the Transvaal attracted a swarm of prospectors to the area. A mere fifteen years later, gold was also uncovered there. Despite treaties recognizing Boer independence in the 1850s, the British annexed the Transvaal and other Boer territories. Following two fierce conflicts known as the Anglo-Boer Wars, the British triumphed and claimed the Transvaal as a part of their colonial empire in South Africa.

Thomas Cullinan, a British-born South African, purchased the land that would later become the Premier Mine in 1902, the same year the Boers handed over control of the Transvaal to the British. In 1905, the remarkable Cullinan diamond was discovered there. The British-controlled Transvaal government purchased the diamond from Cullinan for £150,000 (equivalent to £20 million today or $22 million) in 1907 and gave it as a birthday gift to King Edward VII, who reluctantly accepted it 'as a token of the loyalty and attachment of the people of Transvaal.'

Calls for Repatriation of the Cullinan Diamonds

The Cullinan diamonds, which embellish the Sovereign Scepter and the Imperial State Crown, are typically stored behind bulletproof glass in the Tower of London, where the crown jewels are displayed for tourists. However, the sight of these priceless gems — particularly the Cullinan I, valued at an estimated $400 million — accompanying the Queen’s funeral procession stirred criticism of Britain’s colonial history.

"Clearly, it's long overdue to return these grim symbols of empire as part of a larger reparations movement," journalist Helena Cobban wrote on September 24, 2022. "How many new houses, roads, and bridges could be built... with the sale or repatriation of even a few of these jewels?"

Everisto Benyera, a professor of African politics at the University of South Africa, raised doubts about the legitimacy of the British Transvaal government, which had seized the land from the Boers, who themselves had appropriated it from African tribes.

Regarding King Edward VII and the rest of the royal family, Benyera told CNN, "Receiving a stolen diamond does not absolve the recipient. The Great Star [of Africa] is a blood diamond."

Crown Jewels Like the Cullinan Are Geological Marvels

In 2016, GIA's Smith made headlines when he and his team published groundbreaking research in the journal *Science*, revealing that exceptionally large and strikingly clear diamonds, like the Cullinan, are formed at depths much greater than 99% of the world's gem diamonds—hundreds of miles deep inside Earth.

"Diamonds are already an incredibly unique geological material," says Smith. "However, within the world of diamonds, Cullinan-like diamonds are in a league of their own. They form differently and possess extraordinary characteristics of their own."

Most typical diamonds, those commonly found in engagement rings and earrings, are created at depths ranging from 90 to 125 miles (150 to 200 kilometers) beneath Earth's surface, in the lithosphere—located beneath the thickest sections of the continental plates. At GIA, Smith had the opportunity to study rarer, more valuable diamonds known as CLIPPIR diamonds—an acronym describing these gems' Cullinan-like qualities: large, inclusion-free, pure, irregular, and resorbed.

Inclusions, the tiny mineral specks trapped within diamonds that affect their clarity, are almost nonexistent in CLIPPIR diamonds like the Cullinan. By analyzing the few impurities he could detect in hundreds of large diamonds, Smith concluded that CLIPPIR diamonds likely form at depths closer to 410 miles (660 kilometers), where liquid metal stirs within Earth's mantle.

"Super-deep" diamonds, such as the Cullinan, are pushed to the Earth's surface and mixed with shallower diamonds during a specific type of volcanic eruption known as a "Kimberlite" eruption. Kimberlite magma, which gets its name from the South African city Kimberley, contains higher amounts of water and CO2 compared to typical magma.

"It's like shaking a Champagne bottle and releasing all the pressure," explains Smith. "That's the amount of energy we're talking about."

The largest and most flawless diamonds in the world have been recovered from Kimberlite deposits, many located in South Africa, but also in Brazil and India, the latter being the source of the legendary Koh-i-Noor diamond. The 105-carat Koh-i-Noor, meaning "Mountain of Light" in Persian, was taken from India by the British in the 19th century and became part of the crown jewels.

Following the Queen's death, the Koh-i-Noor, much like the infamous Cullinan diamond, faced renewed calls for its repatriation to India.